Growth and characterization of boron delta function shaped doping layer in silicon by molecular beam epitaxy

Abstract

We have successfully realized boron (delta) -function-shaped doping in the silicon epilayer by molecular beam epitaxy (MBE) with a B<SUB>2</SUB>O<SUB>3</SUB> doping source. The sheet boron concentration N<SUB>(Beta</SUB> ) of the boron (delta) doping layer can exceed 3.4 X 10<SUP>14</SUP> cm<SUP>-2</SUP>. The transmission electron microscopy (TEM) cross-section image shows the width of the (delta) doping layer is about 1.5 nm. Meanwhile, we have applied in situ Auger electron spectroscopy (AES) to quantitatively analyze the relationship of boron (delta) doping sheet concentration N<SUB>(Beta</SUB> ) with the (delta) doping time. With the substrate temperature of 650 degree(s)C and the doping source temperature of 900 degree(s)C, for N<SUB>(Beta</SUB> ) &lt; 3.4 X 10<SUP>14</SUP> cm<SUP>-2</SUP> (1/2 monolayer), boron incorporation onto Si (100) is proportional to the (delta) doping time, and the sticking coefficient is 4.4 X 10<SUP>13</SUP> cm<SUP>-2</SUP>/min; while for N<SUB>(Beta</SUB> ) &gt; 3.4 X 10<SUP>14</SUP> cm<SUP>-2</SUP>, the incorporation tends to saturate. The residual oxygen has not been detected even if N<SUB>(Beta</SUB> ) is up to 4.4 X 10<SUP>14</SUP> cm<SUP>-2</SUP>.